Benzinga's Top #PreMarket Losers

Sunesis Pharmaceuticals SNSS shares slipped 63.10% to $2.45 in pre-market trading as pivotal Phase 3 VALOR trial of acute myeloid leukemia treatment did not meet primary endpoint. Alcobra ADHD dropped 40.04% to $8.46 in pre-market trading following the announcement of topline results from Phase III study of MDX in adult ADHD. EZchip Semiconductor EZCH shares dropped 8.94% to $22.52 in pre-market trading after the company lowered its Q3 sales forecast. H&R Block HRB fell 6.10% to $29.73 in pre-market trading as the company announced that the regulatory approval process for the company's deal with BofI Federal Bank won't be completed this year.